The present invention relates to an image display device for use in a system for displaying camera images in plant control systems, remote conference systems, etc. and a system for using the image display device.
In plant systems and remote conference systems, the states and conditions of remote sites and conference halls are observed by displaying the remote sites and the conference rooms using images taken by a camera. In these systems, the cameras are not always fixed cameras. For example, in the case of plant monitoring systems, there are disposed cameras which are capable of panning and zooming, and an operator sometimes pans the cameras and monitors areas which are not normally in one scene or zooms the cameras to expand the view so as to observe selected areas in detail.
In systems utilizing cameras that are movable for panning or zooming, as mentioned above, images taken in by cameras are displayed on the screens of remote TV""s or computers. Therefore, when cameras pan or zoom, the operators are often not able to judge which sites they are observing. When a camera can pan or zoom, there is a problem that an operator may not know which part of an monitored object he is observing with the camera.
There also another problem in that it is difficult to control a camera to take the image of a specific part, when the specific part of the whole object or scene is to be examined with the specified camera.
An object of the present invention is to solve the above mentioned problems, and to provide an image display device that can display camera images with good usability.
In order to achieve the above mentioned objects, the image display device of the present invention is featured by means for displaying on a screen an image of the whole area that can be taken in by a camera; means for detecting a position of the camera on the screen by detecting the state of the camera, such as the pointing direction of the camera, the zooming ratio, etc.; means for marking the present area on the screen taken in by the camera position detecting means; and means for renewing the whole image on the screen at a predetermined timing.
Another feature of the present invention resides in an image display device having whole image displaying means for displaying an area which is larger than the whole area being viewed by a camera; area specifying means for specifying an area in the whole image; and control means for controlling the camera in such a way as to take images of the area specified by the area specifying means. A whole image taking in means takes images of the whole area viewed by the camera and displays the whole image on the display screen. The camera position detecting means detects the state of the camera panning and zooming so as to predict when the present image being taken by the camera corresponds to a specified part of the whole image in accordance with information concerning the state of the camera. The camera area display means puts marks on the positions at whole image detected by the above camera position detecting means.
A whole image renewal means renews the whole image, in view of the possibility of the image being changed in the future, in accordance with a predetermined timing. Since it is possible to clearly indicate what part or position on the whole image is being viewed, operators need not worry about trying to identify what places they are observing. The area specifying means specifies the area to be viewed by the camera on the whole image displayed by the display means. The camera control means controls the state of panning or zooming of the camera to take in images of an area specified by the area specifying means. Operators are able to correctly and quickly control the camera while easily identifying the specified part being viewed, even when they want to take in images of specified parts of an image.